For Professionals


Technical Information and data about our products are listed below for in depth information that will be useful for professionals or people who would like to learn more. If any more information is needed you can contact us at and we will get back to you as soon as possible.  

How does MVHR work?

ClickVent provides fresh filtered air into a building whilst retaining up to 95% of the energy that has already been used to heat the building. It simply works by extracting air from ‘wet’ rooms within your home e.g. kitchen, bathroom, utility. Extracted air is taken through a central heat exchanger which supplies fresh air to ‘living’ rooms e.g. bedrooms, living rooms, studies etc. If air temperature inside the building is warmer than outside, this heat will be retained, if air temperature is colder inside e.g. in summer, then the coolth is maintained in the building. Ventilation requirements are calculated for individual buildings and achieved within a balanced heat recovery and ventilation system that operates 24hr a day.

The Building Energy Performance Assessment

Thessla Green MVHR Units are listed on the database for the Building Energy Performance Assessment as can be found from clicking the link. AirPackHome 4 300/400/500h are included within this database with the newer models currently being assessed, expectant to be included in the database also.

This database was created to support UK building energy performance assessments that are produced using the National Calculation Methodologies for energy rating buildings (NCMs). The NCMs are a range of assessment methodologies comprising: the Standard Assessment Procedure for Energy Rating of Dwellings (SAP), Reduced Data SAP (RdSAP), which is used to assess existing dwellings, and the Simplified Building Energy Model (SBEM)*, which is used to assess non-domestic buildings. The website also supports assessments undertaken using the BREDEM (BRE Domestic Energy Model) assessment methodology, the parent methodology upon which SAP and RdSAP are based.

Building energy assessment methodologies are used to deliver multiple Government policy initiatives. These range from Building Regulation compliance checks and the production of Energy Performance Certificates, which satisfy the UK’s obligations under the European Performance of Buildings Directive (EPBD), to supporting the Green Deal and Energy Companies Obligation (ECO) schemes by enabling the differentiation of improvements measures. Assessing the performance of a measure is complex and it may not always be possible to describe in terms of a simple number for comparison purposes. In such instances the assessment of performance is only possible using building energy performance assessments that utilise specific product performance data.

Technical Data for MVHR Units and Accessories
Technical data sheets are attached below. These give detailed information and instructions regarding our heat recovery units and accessories.


AirPack 4 

AirPack 4 Dimensions 1

AirPack 4 Technical Data 

AirPack 4 Instructions


AirPack Home

AirPack Home Vertical Technical Data

AirPack Home Horizontal Technical Data

AirPack Home User Manual

AirPack Home Installation Manual


Technical Data Sheet

Control Manual

Specialist Rigid Insulated Ducting
Innovative and sustainable insulated ventilation piping system developed to offer high grade solutions to the increasing demands of comfort climate in residential buildings.

Technical Data Sheet

Health Certification


Anti-bacterial Anti-static Ventilation Ducting

Links below include statistical data for the anti bacterical and anti static properities within our ventilation ducting. Futher information about the product itself is also included.

Ventilation Ducting Data Sheet

Futher information

Pro Interior Extract and Supply Valves

The technical specification for our professional extract and supply valves are linked below and are available in round or square shape in both white and black, so you will find something suitable and subtle for any project. Contact us about any other details.

Extract and Supply Valves Technical Data

Further Info


Technical Data for MVHR Filters

MVHR filters are compatible with their specific units. To discover the correct filter for your unit you can use our selection method on ‘Shop’ under ‘Filters’ or you can contact us directly for advice. Further data sheets and specifications are listed below.

Passivhaus Certification
Passivhaus certification illustrates compliance with a quality assured standard and methodology for low energy building, which can help create buildings which use around 75% less energy than standard practice for UK newbuild. Each element of our system is passivhaus certified so you can be ensured the highest energy efficiency within your home. 

AirPack 4 Passivhaus Certification



You can set up a subscription plan with us to receive new filters for your heat recovery machine on a regular basis. Ensuring the highest efficacy for your system at all times with little effort.

“I had been looking for different ways that I could reduce my energy bills. The ClickVent Easy Fit System was a simple solution to this and it has been an uncomplicated, barely noticeable addition to my home.”